Filter device for filtering gaseous fluids
A filter device for filtering gaseous fluids has a spiral-shaped wound filter path having parallel flow channels for the fluid. The flow channels end in a wound state at an axial face of the filter element at axially different positions. At the second, opposite axial face, the filter element has a geometry deviating from that of the first face.
1. An air filter device for filtration of gaseous fluids in internal combustion engines, comprising:
a spirally wound filter element ( 1 ) including:
a spirally rolled filter sheet ( 7 ) having first and second oppositely positioned axial end faces and provided with parallel extending flow channels ( 2 a , 2 b ) for the fluid extending between said end faces, said spirally rolled filter sheet having radially inwardly positioned windings and radially outwardly positioned windings;
wherein said radially outwardly positioned windings have a different axial length than said radially inwardly positioned windings;
wherein said flow channels of said filter element vary in length with said differing axial lengths of said radially outwardly positioned and said radially inwardly positioned windings;
wherein neighboring flow channels of said parallel flow channels are alternatingly open or closed off at oppositely positioned axial end faces of said filter element;
wherein said parallel flow channels in said rolled state end at different axial positions at one of said axial end faces of said filter element;
wherein said filter element at said second end face is provided with a geometry deviating from that of said first end face;
wherein all of said parallel extending flow channels at the second oppositely positioned end face of the filter element end are positioned in a common end face plane at identical axial positions;
wherein said end face with said parallel extending flow channels ending at identical axial positions forms an inflow side and said oppositely positioned end face forms an outflow side ( 4 ) of said filter element;
wherein said filter sheet ( 7 ) in the not-yet rolled spread-out state forms a generally trapezoidal shape with oppositely positioned parallel terminal edges ( 8 , 9 ) having different lengths;
wherein said terminal edges ( 8 , 9 ) represent the start of rolling or the end of rolling of said filter element;
wherein said second lateral edge ( 11 ) between the terminal edges ( 8 , 9 ) is curved.
2. Filter device according to claim 1 , wherein said oppositely positioned terminal edges ( 8 , 9 ) at one of their terminal points are connected with one another by a first straight lateral edge ( 10 ) that extends at a right angle to the two terminal edges ( 8 , 9 ).
3. Filter device according to claim 1 , wherein an adhesive bead ( 3 ) each is applied onto the filter sheet ( 7 ) along each lateral edge ( 10 , 11 ).
4. Filter device according to claim 1 , wherein said filter sheet ( 7 ) is embodied as a corrugated filter layer ( 15 ).
5. Filter device according to claim 1 , wherein
said oppositely positioned terminal edges ( 8 , 9 ) at one of their terminal points are connected with one another by a first straight lateral edge ( 10 ) that extends at a right angle to the two terminal edges ( 8 , 9 );
wherein said end face of the filter element ( 1 ) where the flow channels ( 2 a , 2 b ) in the rolled state end at different axial positions has a cone shape;
wherein an adhesive bead ( 3 ) is arranged on said filter sheet ( 7 ) along each lateral edge ( 10 , 11 ), said bead securing said filter sheet into form of said spirally wound filter element ( 1 );
wherein said filter sheet ( 7 ) is embodied as a corrugated filter layer ( 15 ).
6. An intake module of an internal combustion engine with a filter device according to claim 1 , wherein the filter device is arranged in an intake passage ( 29 ) with a non-constant cross-section.